The proposed work is in the general theoretical context of studying animal behavior periodicities in connection with ecological factors. Specifically, the nocturnal activity patterns of kangaroo rats (Dipodomys sp.) is under investigation with respect to nocturnal moonlight primarily, and factors such as cover, temperature, and food availability secondarily. Research is done in the field with devices which measure the time of visits to the instruments, and in the laboratory. Results to date suggest that the "standard" laboratory methods of measuring activity produce results which are complete artifacts; the animals behave the opposite of their behavior in the field. However, when certain ecological factors are supplied to the laboratory setting, laboratory behavior closely resembles field behavior.